It’s a while since I’ve posted anything here and this entry is more in the nature of a ‘placeholder’ than a description of actual progress. It is hard to believe that it’s almost three years since I started building my model of GWR No.184, which was the (standard gauge) locomotive that started my interest in earlier locomotive designs.
That model was a fairly simple build, although I did manage to make some basic errors, largely by failing to understand the compromises needed, when designing for the non-prototypical 00 gauge. As a result of these errors, my original model, while looking very attractive, would not run smoothly, because the outside cranks had insufficient clearance from my over-wide outside frames. Because the model looked nice, I was reluctant to pull it all to pieces and start again.
Then I started looking at Broad Gauge models and realised that the standards adopted for these models are usually much finer than those I had been used to, when modelling in 00 gauge. Whereas I had previously been pleased to produce a good ‘impression’ of the prototype, I felt that I should strive for higher standards in my ‘new’ gauge.
As described in previous entries, I managed to overcome the difficulties in building a mail coach, in a condition appropriate for the 1860s, and then started looking at an appropriate locomotive for a mail train. I already have a ‘Rover’ class ‘single’ built from a K’s ‘Milestones’ kit, which has allowed me to built a small diorama, including the mail coach.
My aim, however, was to construct a ‘Waverley’ class 4-4-0, by using the Broad Gauge Society (BGS) kit of a Gooch Standard Goods to provide the boiler. The BGS kit presented some difficulties but I eventually succeeded in completing the boiler assembly and also constructed a pair of inside ‘sandwich’ frames.
It was not difficult to produce a similar set of inside frames for the 4-4-0 and so generate a basic framework for the new locomotive.
It than became apparent that further progress was going to be more difficult than I had anticipated and, as a result, I have been pondering various possibilities.
The exposed driving wheels, with their bicycle-like splashers, are such a large part of the ‘character’ of these locomotives that I feel it is essential to achieve a good representation of these features. I suspect that it will be very difficult to cut out suitable shapes, by hand, in thin brass sheet, without introducing distortions that will spoil the overall effect. In another thread in these forums, however, I read a discussion of electrolytic etching, which seems to offer a potentially useful technique for making those rather demanding outside splashers. This method will, however, require a lot of experimentation, before I shall be able to produce suitable components.
I am still unsure, however, whether this will result in a strong enough structure to provide both a good appearance and appropriate clearance around the wheels, to achieve smooth running. My current thought is to cut out some components in plasticard, by using my Silhouette cutter. If only the cutter could work on brass sheet!
My other thought is to provide a separate internal chassis to hold the running gear in a sort of ‘bogie’, which will make my current, rather lightweight frames purely ‘cosmetic’. This would mean building a small chassis, very similar to that which I built for No.184, and mounting it underneath the firebox of the existing boiler. An advantage, arising from this, would be that I could suspend the resulting ‘bogie’, to provide some flexibility in the wheelbase of this rather long 4-4-0.
My last concern is whether I’ll be able to obtain wheels that will adequately capture the appearance of the real locomotive. There seems to be no commercial source of 4mm scale, 24-spoke 7-foot driving wheels so, again, I shall probably have to make a compromise. Otherwise, I’ve been contemplating whether I could possibly build my own spokes inside a commercial 28mm diameter rim.
So, my current problem is that of seeing many difficulties and not yet being sure of how best to overcome them. It may take some time but my experience is that, eventually, a solution will become clear.
In fact, this has recently happened in the case of No.184, where I realised that I could cut away the existing outside frames, without damaging the rest of the model. I then used some short lengths of BGS bridge rail, to strengthen the remaining part of the chassis and to provide attachment points for new outside frames, at a narrower spacing.
This has given me the free-running that is needed, so that it is worth continuing to add a motor and gearbox, to complete that model